Correlation of Serum Leptin with Body Mass Index and Insulin Resistance in Polycystic Ovarian Syndrome in a Tertiary Care Centre of Southern Odisha, India

Introduction: Leptin is an adipocyte derived hormone encoded by ob gene which serves as a relay link between metabolic signals and brain that regulate the hypothalamic pituitary ovarian axis. Leptin is related with obesity which is a most important cause of Polycystic Ovarian Syndrome (PCOS) in women of reproductive age group. Aim: To evaluate leptin concentration and to analyse its correlation with Body Mass Index (BMI) and insulin resistance in PCOS. Materials and Methods: This case-control study was conducted from December 2018 to December 2019 at Department of Biochemistry in collaboration with Department of Obstetrics and Gynaecology, MKCG Medical College and Hospital, Berhampur, Odisha, India. A total of 60 PCOS subjects, aged between 15-30 years (30 obese PCOS and 30 lean PCOS) and 30 age matched, normal ovulatory healthy controls were included in the study. Parameters such as serum leptin, fasting plasma insulin, Homeostatic Model Assessment-Insulin Resistance (HOMA-IR), Fasting Plasma Glucose (PPG), Postprandial Plasma Glucose (PPPG) were estimated using commercial kits. One-way Analysis of Variance (ANOVA) test was used for data analysis and the Pearson's correlation method was used to find the correlation between the parameters. Results: The mean age of women in all the three PCOS groups was found to be 22.4 +/- 3.13 years. The BMI of obese PCOS patients (31.9 +/- 4.7 kg/m2) and lean PCOS patients (21.4 +/- 2.2 kg/m2) were higher than that of healthy controls (20.7 +/- 1.8 kg/m2) which was statistically significant (p-value < 0.001). The serum leptin in obese PCOS were significantly higher (28.0 +/- 17.8 ng/mL) than lean PCOS (5.8 +/- 2.2 ng/mL) and fasting plasma insulin in lean PCOS were (10.9 +/- 2.4 mu IU/mL) significantly lower than obese PCOS (30.2 +/- 14.8 mu IU/mL). Mean serum leptin levels had significant positive correlation with BMI in lean and obese PCOS and insulin resistance in obese PCOS. Conclusion: In the present study, high leptin concentration was observed in PCOS patients and there was positive correlation of leptin with BMI in both lean and obese PCOS groups and leptin was positively correlated with insulin resistance in obese PCOS.